🎵 Music
MP3/AAC/FLAC/WAV from SD, artist/album/playlist browser, ID3 tags (cached), shuffle & repeat, sleep timer, resume after reboot.
Fennek turns the LilyGO T-Deck Pro (ESP32-S3, E-Ink, LoRa) into a real handheld: listen to music, resume audiobooks, read eBooks and chat over the LoRa mesh via MeshCore — with a homescreen launcher, touch + physical keyboard, and background audio that keeps playing across app switches.
It is a standalone alternative to the factory firmware — built around the hardware's defining quirk, that E-Ink, the SD card and LoRa all share one SPI bus, while still delivering stutter-free audio playback.
Apps
🎧 Audiobook
Books as folders under /audiobooks, chapters natural-sorted, per-book bookmark, ±30 s jumps, sleep timer.
📖 Reading
.txt and .epub from /books, on-device EPUB conversion, page-index cache, per-book reading position.
📡 Mesh
Lean MeshCore client: public & hashtag channels, DMs with delivery status, contacts from adverts, message log on SD with history reload.
🎮 Games
2048, Minesweeper, Chess (Negamax AI) and Tic-Tac-Toe — game logic host-tested.
📝 Notes
One note per day under /notes. "+ Today" opens or appends; list shows every day newest-first with a preview.
⚙️ Options
Radio presets (EU Narrow), individual LoRa parameters, node name, battery info, firmware version.
＋ More
Status line (battery, playback), key-lock & standby via the button, and a serial debug console over USB.
On the device
Rendered pixel-accurately from the real drawing code (240×320 E-Ink).
The defining quirk
On the T-Deck Pro, E-Ink, the SD card and LoRa share one SPI bus. The entire architecture revolves around audio never stuttering despite that, and inputs responding instantly:
- A dedicated audio-decode task on core 0, with a 256 KB PSRAM read-ahead.
- Every SPI access (SD, E-Ink, LoRa) serialized behind one mutex.
- The SPI bus is released during the E-Ink BUSY phase so the I2S DMA never runs dry.
- E-Ink refreshes only on real change; progress shown as a narrow region strip.
The full set of anti-stutter invariants lives in
CLAUDE.md.
Hardware
LilyGO T-Deck Pro V1.1:
- ESP32-S3 — 16 MB flash, 8 MB PSRAM
- E-Ink GDEQ031T10, 240×320
- CST328 touch (I2C), TCA8418 keyboard
- PCM5102A DAC (I2S, 3.5 mm jack)
- SX1262 LoRa, BQ27220 fuel gauge, microSD
Build & flash
Prerequisite: PlatformIO. Connect via USB-C, then:
pio run -e fennek # build
pio run -e fennek -t upload # flash (USB-C)
pio device monitor -b 115200 # log + debug consoleRuns even without an SD card. Custom firmware replaces the factory software — flash at your own risk.